The extensions to the IPA also define a bilabial percussive ([ʬ]) for striking the lips together (smacking the lips). A lip-smack in the non-percussive sense of the lips noisily parting would be [ʬ↓].[2]

The IPA chart shades out bilabial lateral consonants, which is sometimes read as indicating that such sounds are not possible. The fricatives [ɸ] and [β] are often lateral, but no language makes a distinction for centrality so the allophony is not noticeable.